Raw data and Matlab code for: Convergence in carnivorous pitcher plants reveals a mechanism for composite trait evolution

AbstractComposite traits involve multiple components that, only when combined, gain a new synergistic function. Thus, how they evolve remains a puzzle. We combined field experiments, microscopy, chemical analyses and laser Doppler vibrometry with comparative phylogenetic analyses to show that two carnivorous Nepenthes pitcher plant species convergently evolved identical adaptations in three distinct traits to acquire a new, composite trapping mechanism. Comparative analyses suggest that this new trait arose convergently via ‘spontaneous coincidence’ of the required trait combination, rather than directional selection in the component traits. Our results indicate a plausible mechanism for composite trait evolution and highlight the importance of stochastic phenotypic variation as a facilitator of evolutionary novelty.
MethodsData were collected from 55 Nepenthes pitcher plant species from Botanical collections in the UK, Germany and Switzerland, as well as from two species (N. gracilis and N. pervillei) from natural populations in Borneo and the Seychelles. Fotos and high-speed videos were used to assess two macromorphological traits: (1) lid orientation (deviation from horizontal in °), and (2) lid loading/impact response (qualitatively from Fotos, and quantitatively from high-speed video recordings). Laser Doppler vibrometry was used for detailed analysis of lid oscillations after a drop impact on the lid. Scanning electron microscopy was used to assess surface microtopography (images are shown in the article supplementary material, Figures S1 and S2, and are not included in this dataset). Gas-chromatography mass-spectrometry was used to investigate the chemical composition of surface waxes. For detailed descriptions of the experimental methods and sampling techniques see online supplementary material, Materials and Methods.
Usage notesNo specialist software is required. Data files are in .csv format. Images are in .tif format. Video files are in .avi format.

摘要
复合性状（composite traits）包含多个组分，仅当这些组分相互结合时，才能获得全新的协同功能。因此，这类性状的演化机制始终是一个未解之谜。本研究结合野外实验、显微观测、化学分析、激光多普勒振动测量法（laser Doppler vibrometry）与比较系统发育分析（comparative phylogenetic analyses），证实两种食肉猪笼草（Nepenthes pitcher plant）物种通过趋同演化，在3个独立性状上形成了完全一致的适应性特征，从而获得了全新的复合捕食机制。比较分析结果显示，该新性状的趋同演化并非源于组分性状的定向选择，而是通过所需性状组合的“自发偶合”实现。本研究结果为复合性状的演化提供了一种合理的机制，并凸显了随机表型变异作为演化新性状促进因子的重要性。
方法
研究数据采集自英国、德国与瑞士的植物馆藏标本中的55种猪笼草，以及采自婆罗洲与塞舌尔自然种群的2个物种：N. gracilis与N. pervillei。本研究通过图像与高速视频评估了2项宏观形态性状：（1）瓶盖朝向（与水平面的偏差角度，单位：°）；（2）瓶盖承重/冲击响应（通过图像进行定性分析，通过高速视频录制进行定量分析）。采用激光多普勒振动测量法对瓶盖受液滴冲击后的振荡行为开展详细分析。采用扫描电子显微镜（scanning electron microscopy）评估表面微观形貌（图像详见论文补充材料图S1与S2，本数据集未包含）。采用气相色谱-质谱联用法（gas-chromatography mass-spectrometry）对表面蜡质层的化学成分进行分析。实验方法与采样技术的详细描述请参见在线补充材料“材料与方法”。
使用说明
无需专用软件。数据文件格式为.csv，图像文件格式为.tif，视频文件格式为.avi。